Exploring pollutant joint effects in disease through interpretable machine learning.

Identifying the impact of pollutants on diseases is crucial. However, assessing the health risks posed by the interplay of multiple pollutants is challenging. This study introduces the concept of Pollutants Outcome Disease, integrating multidisciplinary knowledge and employing explainable artificial intelligence (AI) to explore the joint effects of industrial pollutants on diseases. Using lung cancer as a representative case study, an extreme gradient boosting predictive model that integrates meteorological, socio-economic, pollutants, and lung cancer statistical data is developed. The joint effects of industrial pollutants on lung cancer are identified and analyzed by employing the SHAP (Shapley Additive exPlanations) interpretable machine learning technique. Results reveal substantial spatial heterogeneity in emissions from CPG and ILC, highlighting pronounced nonlinear relationships among variables. The model yielded strong predictions (an R of 0.954, an RMSE of 4283, and an R2 of 0.911) and emphasized the impact of pollutant emission amounts on lung cancer responses. Diverse joint effects patterns were observed, varying in terms of patterns, regions (frequency), and the extent of antagonistic and synergistic effects among pollutants. The study provides a new perspective for exploring the joint effects of pollutants on diseases and demonstrates the potential of AI technology to assist scientific discovery.

Toward a comprehensive life-cycle carcinogenic impact assessment: A statistical regression approach based on cancer burden.

The current approach to life cycle carcinogenic impact assessment (LCCA) is hindered by its static and linear characteristics. This situation prevents the accurate prediction of the incidence, associated damage, and potential economic burden of cancer. This study explores a highly comprehensive pathway for LCCA assessment. It uses the impacts of Tracheal, bronchus, and lung (TBL) predicted by the LCCA of China's coal power industry through a screened statistical regression model as the research target. The latest global burden of disease estimates is utilized to quantify the health damage from TBL incidence, whereas an approach combining the actual cost of health and human capital is applied to further assess the economic burden of TBL. Findings indicate that the traditional and static LCCA method, which relies on animal toxicity data, can lead to underestimations in actual LCCA. The interaction among spatiotemporal meteorological factors, epidemiological cancer disease burden, and socioeconomic behaviors allows exhibits nonlinearity due to the changes in the combined toxicity of mixed key substances. Following the active implementation of ultralow emission and energy-saving transformations in China's coal power industry, the national percentage of TBL cancer incidence caused by pollutants from the coal power industry decreased from 25.2 % in 2004 to 11.5 % in 2020. Results indicate that the established dynamic LCCA model based on temporal and spatial climate, socioeconomic, and epidemiological cancer data can be feasibly employed for the accurate impact evaluation and mitigation of carcinogens in practical applications.

Towards sustainability: An integrated life cycle environmental-economic insight into cow manure management.

Waste management signifies an equilibrium between environmental and economic factors. However, a comprehensive understanding of the integrated life cycle environmental-economic performance of waste management activities remains unclear. To facilitate a systematic linkage between the economic and environmental sectors, a regionalized life cycle assessment-based life cycle costing method was developed based on China's actual status quo. The cow manure utilization was set as an entry point to explored long-term environmental-economic performance of milk production under various manure utilization pathways. The results show that trade-offs were observed between internal and external costs as well as various environmental indicators. The choice of waste utilization is the focal point of environmental-economic trade-offs in the cow raising system. The optimal environmental-economic performance was achieved through the manure fertilizer utilization pathway, yielding a remarkable three-fold increase in marginal environmental benefits. Compared with fertilizer utilization, the manure direct returning to field reduced the carbon footprint by 12% while induced an external cost of $14.3. The wastewater treatment pathway is $ 5.5 lower in internal costs but $ 11.7 higher in external costs than those of fertilizer utilization. Overall, utilizing manure has potential to mitigate the upward trend of carbon footprint and external costs. However, achieving the carbon peak remains a significant challenge. A promising solution is the recycling of straw resources within cropping systems, particularly in hotspot regions (e.g., Inner Mongolia, Heilongjiang, Hebei, and Shandong). A comprehensive analysis of the dynamic interplay between cropping systems and cow raising systems is critical steps towards realizing a carbon-neutral future within the dairy production.

Uncovering the energy-carbon-water footprint of waste rubber recycling: Integrated environmental and economic perspectives.

The commitment to waste management has gained increasing momentum as global waste generation continues to skyrocket and threaten the environment. However, detailed assessments and clear insights remain absent to address the global waste utilization conundrum. This study evaluated the impact-oriented energy, carbon, and water (ECW) footprints of three typical scenarios for a waste recycling activity (i.e., waste rubber recycling) from environmental and economic dimensions, and explored key factors, nexus characteristics, and optimization measures. Results indicated that the rubber powder as an asphalt modifier scenario had a 93% greater environmental impact and 87% higher economic cost compared with the pyrolysis and reclaimed rubber production scenarios. Key processes, such as direct processes, electricity generation, and transportation, were identified as the major contributors to the ECW footprints, with the internal costs of raw materials, equipment, and taxes coupled with the external costs of human health dominating the economic impact. The nexus analysis results highlighted the urgent need to optimize the energy system for waste rubber recycling. Greening the production process revealed the benefits, with natural additives mitigating 85% of the environmental burden and 97% of the external costs compared with conventional additives. Industrial green microgrids, clean energy generation, proximity waste management, and electrified transportation were explored to foster sustainable optimization of waste rubber recycling systems. Moreover, a joint tax-subsidy mechanism for rubber production-recycling systems can stimulate recycling-oriented product design and increase the motivation to recycle waste rubber.

How can ecosystem status be more comprehensively reflected? A case study of Jinan City, China.

Ecosystems provide benefits to human well-being, but highly concentrated human activities also cause environmental pressure. Previous studies focused only on one aspect: either ecosystem services (ESs) or ecosystem damage (ED). To provide comprehensive view of ecosystem status in the selected study area, an integrated ecosystem performance analytic framework was established based on the ED-ESs synergistic effect. This study quantitatively analyzed the dynamic variation in ecosystem status from both ED and ESs perspectives with a case study of Jinan City, China, from 2000 to 2020. The results showed that the environmental and economic impacts caused by pollution were 692.87 species.year and $15.58 × 108 in 2020, respectively, and they were mainly derived from energy consumption. Regarding ESs, three regulating services (water retention, soil retention, and carbon sequestration) increased from south to north, whereas material services presented the opposite trend. Ecosystem service value had declined after peaking in 2010 when material services contributed the most. Overall, the Jinan City suffered from ecosystem decline, with ecosystem performance on a downward trend from 2000 to 2020. Finally, the characterization factors of four ESs were appropriately incorporated into the life cycle impact assessment to drive the evolution in ecosystem performance calculations.

Environmental footprints of soybean production in China.

As a significant protein source for humans and animals, soybean (Glycine max) has experienced a fast growth with the rapid development of population and economy. Despite broad interest in energy consumption and CO2 emissions generated by soybean production, there are few impact-oriented water footprint assessments of soybean production. This study evaluates the fossil energy, carbon, and water footprints of China's soybean production so that key environmental impacts can be identified. To provide reliable results for decision-making, uncertainty analysis is conducted based on the Monte Carlo model. Results show that the impact on climate change, ecosystem quality, human health, and resources is 3.33 × 103 kg CO2 eq (GSD2 = 1.87), 6.18 × 10-5 Species·yr (GSD2 = 1.81), 3.26 × 10-3 Disability-adjusted Life Years (GSD2 = 1.81), and 81.51 $ (GSD2 = 2.28), respectively. Freshwater ecotoxicity is the dominant contributor (77.69%) to the ecosystem quality category, while climate change (85.22%) is the dominant contributor to the human health category. Key factors analysis results show that diammonium phosphate and diesel, and on-site emissions, are the major contributors to the overall environmental burden of soybean production. Several policy recommendations are proposed, focusing on trade structure optimization, efficient resource use, and technological improvements. Such policy recommendations provide valuable insights to those decision-makers so that they can prepare appropriate mitigation policies.

Strategies for improving the environmental performance of nickel production in China: Insight into a life cycle assessment.

Nickel is a critical metal for global low-carbon energy transition, but its production processes require massive energy inputs and emit large amounts of pollutants. This study constructed life cycle inventories of the mainstream electrolytic nickel production chains in China at the industrial level and subsequently evaluated their environmental performance via a regionalised life cycle impact assessment method. Results show that environmental indicator results of the electrolytic nickel production from the leaching electrowinning method were 17.7%-40.2% lower than those from the grind and flotation electrolytic method. At the endpoint level, the nickel mining and beneficiation stages contributed 54.7%-65.91% of human health damage, 83.0%-84.7% of ecosystem quality damage and 80.8%-83.7% of resources damage. The key processes, including direct processes, cement input and energy consumption (e.g., electricity and coal), accounted for more than 62.1% of the impacts in the key midpoint categories. The potential environmental damage of China's nickel mining and beneficiation industry increased by 29.2% from 2010 to 2018 because of the growing trend of nickel ore demand. In the case that China's nickel metal recovery rate reaches the global average level, then approximately 3.83 × 102 Daly of human health damage, 59.83 Species·year of ecosystem quality damage and 1.64 × 108 $ of resources damage can be avoided annually. Strategies for promoting the full assimilation of renewable electricity, applying the clinker-free cemented backfill materials in the mining process, precious recovery by bioleaching from tailings and reusing waste rock as building materials are recommended. Meanwhile, extended producer responsibility should to be comprehensively implemented in the nickel-related industries to alleviate the environmental implications and nickel supply pressures from geo-mining.

Does it pay to develop a ground source heat pump system? Evidence from China.

The application potential and environmental benefits of ground source heat pump (GSHP) systems have become the focal points of decarbonization in the building sector. Synchronized and scientific analysis of GSHP systems' environmental and economic performance, however, remains lacking. This study analyzes the application prospects of GSHP systems via a life cycle assessment-based life cycle costing method, and considers China's actual status quo. The internal and external annual costs of a GSHP system per square meter are $ 4.05 and $ 1.37, respectively. Electricity generation and steel production are key processes to improve the environmental performance of a GSHP system further. Compared with coal-based heating, a GSHP system can mitigate 65%-95% of the environmental impact and 85% of external costs, except for the metal depletion impact which is 1.5 times higher than that of coal-based heating. In Shandong Province, promoting GSHP systems can substitute up to 69.4% of the district heating area, which implies reductions in fossil depletion, greenhouse gas emissions, human health impact, ecosystem quality impact, and external costs by up to 2.37 × 1010 kg oil eq, 1.08 × 1011 kg CO2 eq, 3.87 × 105 DALY, 1.18 × 103 Species. year, and $ 2.51 × 1010, respectively. In consideration of environmental and economic aspects, a GSHP system can exhibit benefits compared with coal-based heating after 2.34 years of operation. To improve the economic and environmental performance of GSHP systems, a series of recommendations on financial subsidies, renewable energy development, inter-regional power transmission, steel scrap utilization, and hydrogen reduction steelmaking is provided.

Insights into the vertical distribution of the microbiota in steel plant soils with potentially toxic elements and PAHs contamination after 60 years operation: Abundance, structure, co-occurrence network and functionality.

Both potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs) are widely present in soil contaminated by steel industries. This study assessed the vertical variation (at 20 cm, 40 cm, 60 cm, 80 cm, 120 cm, and 150 cm depth) of bacterial abundance, community structure, functional genes related to PAHs degradation, and community co-occurrence patterns in an old steel plant soils which contaminated by PTEs and PAHs for 60 years. The excessive PAHs and PTEs in steel plant soils were benzo (a) pyrene, benzo (b) fluoranthene, dibenzo (a, h) anthracene, indeno (1,2,3-c, d) pyrene, and lead (Pb). The abundance and composition of bacterial community considerably changed with soil depth in two study areas with different pollution degrees. The results of co-occurrence network analysis indicated that the top genera in blast furnace zone identified as the potential keystone taxa were Haliangium, Blastococcus, Nitrospira, and Sulfurifustis. And in coking zone, the top genera were Gaiella. The predictions of bacterial metabolism function using PICRUSt showed that the PAHs-PTEs contaminated soil still had the potential for PAHs degradation, but most PTEs negatively correlated with PAHs degradation genes. The total sulfur (TS), acenaphthene (ANA), and Zinc (Zn) were the key factors to drive development of bacterial communities in the steel plant soils. As far as we know, this is the first investigation of vertical distribution and interaction of the bacterial microbiota in the aging soils of steel plant contaminated with PTEs and PAHs.

Carbon, energy and water footprints analysis of rapeseed oil production: A case study in China.

As the largest consumer of rapeseed oil in the world, China should consider the environmental effect of rapeseed oil production. However, only a few improvement measures have been proposed. To fill this gap, this study analyzed the energy, carbon and water footprints of rapeseed oil production based on the International Organization for Standardization standards using the framework of life cycle assessment. Results show that most of the energy, carbon, and water footprint of rapeseed oil production can be contributed to the direct processes of rapeseed cultivation, and the indirect processes of transport and fertilizer/diesel production. The value of energy and carbon footprints are calculated as 726.07 kg oil eq and 3889.75 kg CO2 eq, respectively. For the water footprint, the values of acidification, aquatic eutrophication, carcinogens, freshwater ecotoxicity, water scarcity, and non-carcinogens are 14.24 kg SO2 eq, 4.53 kg PO4-3 eq, 6.72 × 10-5Case, 5.43 × 104 PAF.m3.d, 437.62 m3 deprived, and 1.88 × 10-5 case, respectively. Spatial analysis shows that the total environmental impacts of rapeseed production are concentrated in Sichuan, Hunan, Hubei, and Jiangxi Provinces. Correlation analysis reveals the positive correlation of human health and ecosystem quality with fertilizer application and pesticide loss. In general, the environmental effect can be effectively reduced by adjusting the industrial layout to shorten the distance of transport, improve the fine cultivation degree in low-yield areas, and decrease the use of pesticides in the hilly region of southern China.

Water footprint coupled economic impact assessment for maize production in China.

Nowadays, agricultural production places an enormous burden on freshwater resources, and the environmental external cost caused by the restoration of water quality degradation has attracted great attention. Maize is regarded as one of the world's major food security crops, and China is the second-largest maize producer. Thus, this study conducts an impact-oriented water footprint coupled economic impact assessment to quantify the water-related environmental impacts and economic burden caused by China's maize production from 2008 to 2017. Results show that the overall damage to human health and ecosystem quality of China's maize production in 2017 were 4.32 × 104 DALY and 4.62 × 103 Species·yr, respectively. The total economic cost was $ 2.15 × 1011, which included an internal cost of $ 5.99 × 1010 and external cost of $ 1.55 × 1011. Key factor analysis demonstrates that diesel and fertilizer production dominated the reduction in ecological and external cost burdens. Direct water consumption and labor cost played leading roles in human health and internal cost, respectively. The spatiotemporal variation assessment indicates that Inner Mongolia and Heilongjiang were the hotspots for water footprint and economic impact assessment results after considering the yield factor. The national average water footprint and economic impact caused by producing 1 ton of maize showed an upward trend from 2008 to 2015, however, a significant decline transpired later. Overall, improving the resource efficiency (i.e., diesel and freshwater), scientific application of fertilizer and reducing labor input can further lessen the water footprint and economic impact of maize production. Developing the social environment can also generate indirect environmental and economic benefits to China's maize production.

Economic transition and industrial sulfur dioxide emissions in the Chinese economy.

China transitioned into "new normal phase" during 2007 to 2017, shifting from pursuing rapid GDP growth to a win-win state of economic development and environmental improvement. Using the input-output (IO) table for 2007-2012 and the latest IO table for 2012-2017, an IO model of China's industrial SO2 emissions is established and structural decomposition analysis (SDA) is applied to examine the changes in industrial SO2 emissions resulting from this economic transition. Five influencing factors (emission intensity, production technology, final demand expenditure, final demand structure and economic scale) are taken into consideration. The analysis shows that emission intensity and economic scale are the most influential factors on SO2 emissions. Emission intensity reduced SO2 emissions by 16,560,886 t in 2012-2017 whilst economic scale increased SO2 emissions by 473,490 t. Compared with the period 2007-2012, the contribution rate of emission intensity increased from -82.3% to -189.2%, while that of economic scale decreased from 131.8% to 54.1%. The total contributions of 5 factors to SO2 reduction increased from -5,249,417 t to -12,783,248 t, and the contribution rate increased from -24.8% to -146%. China's energy conservation and emission reduction has achieved remarkable results between 2007 and 2017. In "new normal phase", the slowing of China economic growth, the transition of economic development, industrial structural adjustment and rational consumption habits have had significant effects in reducing environmental pollution.

Life cycle assessment of ultra-low treatment for steel industry sintering flue gas emissions.

The largest contributor to pollutant emissions is the sintering process in steel industry. Ultra-low emission policy for the Chinese steel industry states that emission concentrations of particulate matter, SO2 and NOx should not exceed 10, 35 and 50 mg/m3 respectively. The emission concentrations of the steel industry are the same as the ultra-low emission policy for the coal-fired power industry, but the pollutant control technologies of the two industries are different. Life cycle assessment method is applied to analyze the latest ultra-low treatment process for sintering flue gas emissions which includes electrostatic precipitation, ozone oxidation, wet desulfurization, wet denitration, condensation dehumidification and wet electrostatic precipitation. Following this novel ultra-low emission treatment, the concentrations of particulate matter, SO2, NOx, and PCDDs in the sintering flue gas decreased very significantly, attaining the new emission standard. With 1 ton of sinter as the functional unit and "cradle to gate" as the system boundary, the environmental impact of the process is 0.1811 and the total economic cost is 172.79 RMB, of which internal cost is 34.64 RMB and external cost is 138.15 RMB. The main environmental impacts result from applying the wet denitration and ozone oxidation processes. Sodium sulfite in the wet denitration process, and electricity and liquid oxygen in the ozone oxidation process are the key inputs that cause environmental impact. These findings are useful for a further optimization of the ultra-low emissions process from both the environmental and economic perspective, which is applicable in other regions of the world.

Integrated assessment of the environmental and economic effects of "coal-to-gas conversion" project in rural areas of northern China.

Northern China suffers from serious air pollution especially in winter, much of which derives from solid fuel used for domestic heating in rural areas. In order to reduce pollution emissions in the heating season, the Chinese government has introduced a "coal-to-gas conversion" policy, promoting a switch to natural gas which is much cleaner than the coal normally used for winter heating. The "coal-to-gas conversion" project will cover more than 1.8 billion m2 of heated built floor area and affect more than 12 million heat users in Beijing, Tianjin, Hebei, and the surrounding areas. Life cycle assessment and life cycle cost methods are applied to compare and analyze the environmental impact and economic cost of household energy usage for the whole year under 5 scenarios before and after "coal-to-gas conversion." In the three scenarios after "coal-to-gas conversion," the environmental impact decreases by around 50% while the total economic cost increases by around 80%. Particulate emissions responsible for air pollution are considerably reduced with accompanying benefits for human health, though significant, but reduced, impacts on freshwater and marine ecotoxicity remain. Improving thermal efficiency through natural gas utilization, implementing an energy-saving retrofit of rural housing, and promoting straw utilization yield benefits for people and the environment in rural areas of northern China.

PET bottles recycling in China: An LCA coupled with LCC case study of blanket production made of waste PET bottles.

A large number of polyethylene terephthalate (PET) bottles are discarded daily after usage. Thus, plastic bottle recycling has elicited considerable attention in recent years. In this context, this study aims to quantify the environmental and economic impacts of blanket production from 100% recycled waste plastic bottles in China through a life cycle assessment coupled with life cycle costing method. In addition, the environmental impact of replacing coal with natural gas and solar energy was evaluated. Results show that impact categories of global warming and fossil depletion have significant influence on the overall environment. Carbon dioxide, water, iron, coal and chromium (VI) to water are the main contributors to the overall environmental burden. The internal and external costs are $6433/metric ton and $370/metric ton, respectively. Analysis results indicate that the optimization of organic chemicals, recycled polyester filament and steam production processes can reduce environmental and economic burdens substantially. Energy substitutions with natural gas and the use of solar photovoltaic in steam production and electricity generation are effective measures for decreasing environmental impacts. Finally, suggestions based on research results and the current status of waste plastic bottle recycling in China are proposed.

Life cycle assessment of rare earths recovery from waste fluorescent powders - A case study in China.

Life cycle assessment of recycling rare earths from waste fluorescent powders was conducted, including the uncertainty and sensitivity analyses. Three scenarios were set in this study, namely, recycling with/without final disposal and waste fluorescent powders landfill. Recycling with final disposal presented lower environmental burden than that without final disposal due to the significant reduction of direct emissions. The evident impacts from chemicals and energy production stages were considered the main contributors to the overall environmental burden of recycling with final disposal due to their relatively high emissions of particulates matter, sulfur dioxide, heavy metals, and carbon dioxide as well as the use of fossil fuel. Compared with landfills, rare-earth recycling shows the highest environmental benefits because of the substitution of primary rare earths. To relieve the high demand of rare earths and reduce the overall environmental burden, governments are highly recommended to increase recycle rate, create a complete management system, improve energy consumption and wastewater treatment efficiency, and build an adequate recycle standard.

Life cycle assessment of autoclaved aerated fly ash and concrete block production: a case study in China.

With the rapid development of construction industry, consumption of concrete block has increased rapidly in China. As a kind of green building material and resource comprehensive utilization product, autoclaved aerated fly ash and concrete block have better performance in terms of heat preservation, sound insulation, and fire resistance. However, some typical issues are associated with autoclaved aerated fly ash and concrete block production process such as energy and material consumption as well as pollutant emissions. To examine the environmental and economic impacts of its production process is imperative. Choosing 1 m3 of autoclaved aerated fly ash and concrete block product as functional unit and "cradle to gate" as system boundary, a life cycle inventory is developed. The key processes and key materials with significant environmental impact are identified. Results show that the top four environmental impact categories are marine ecotoxicity, freshwater ecotoxicity, freshwater eutrophication, and human toxicity. Key processes are fly ash slurry production, lime grinding, and steam curing processes. These processes account for 46.58%, 26.00%, and 19.62% of the total environmental load respectively. The key materials are cement, lime, and natural gas, which account for 44.91%, 22.79%, and 20.61% respectively of overall environmental impact. Sensitivity analysis shows that the fly ash slurry production should be optimized preferentially, followed by lime grinding and steam curing processes. These findings are helpful to facilitate the sustainable production of autoclaved aerated fly ash and concrete block.

Impact-oriented water footprint assessment of wheat production in China.

Water consumption and pollution in wheat production, which are worth paying attention in agricultural countries and arid regions, need to be assessed systematically and comprehensively. China, one of the largest wheat-producing country in the world, should be concerned about this issue. Thus, an impact-oriented water footprint assessment of wheat production in China was conducted based on the ISO 14046 standard to quantify water-related environmental impacts. We quantified the environmental impacts on human health and ecosystem quality categories of wheat production from 2009 to 2016 and evaluated the spatial variation of these categories in 2016. Results showed that the environmental impacts on human health and ecosystem quality categories in 2016 were 5.15 × 10-4 DALY/t and 37.17 PDF·m2·yr/t, respectively. Key factor analysis showed that the overall environmental impacts were primarily derived from fertilizer production, diesel production, and direct water consumption and emission. The dynamic analysis results revealed that the temporal variations in impacts were associated with water and fertilizer consumption. Areas with high potential impacts were mainly congregated in the North China Plain and Xinjiang Province due to their high wheat yields. Ecosystem quality was negatively correlated with wheat yield, and human health was positively correlated with crop water requirement. Therefore, on the basis of ensuring grain production, improving the utilization efficiency of irrigation water and reducing fertilizer and diesel consumption are the priorities for the management of agricultural water resources.

Investigating vulnerability of ecological industrial symbiosis network based on automatic control theory.

System fluctuations of eco-industrial symbiosis network (EISN) organization due to disturbance are very similar to the controller adjustment in the automatic control theory. Thus, a methodology is proposed in this study to assess the vulnerability of EISN based on the automatic control theory. The results show that the regulator plays a key role to enhance the resilience of the network system to vulnerability. Therefore, it is imperative to strengthen the real-time regulation and control of EISN so that the system stability is improved. In order to further explore the impact of various regulations on the system vulnerability, the influence of system stability is simulated by means of proportional, differential, and integral control. A case study with Guigang eco-industrial park (EIP) was undertaken to test this model. The results showed that when the system was disturbed at different positions, the key nodes which had great influence on system vulnerability could be selected according to the magnitude of simulation curve. By changing the ratio coefficient of proportional, differential, and integral units to adjust the ecological chain network, the system's resilience to vulnerability can be enhanced. Firstly, if basic conditions of EISN organization remain unchanged, the integral control of the policy support and infrastructure sharing should be strengthened. Secondly, the differential regulation should be improved continuously for the technological innovation capability of key node enterprises. Finally, the key chain filling projects should be introduced for proportional control so that the chain network design can be optimized from the source.

Life cycle assessment and water footprint evaluation of crude steel production: A case study in China.

China, as the world's largest crude steel producer, is suffering from water scarcity and pollution. However, only a few systematic analyses on the environmental burdens and improvements of China's crude steel production have been conducted. Therefore, it is important for research to be done how China's steel industry can be improved in environment management. To help decision-makers understand this, a life cycle water footprint analysis including gray and blue water was performed based on the methodology prescribed in the ISO 14046 standard. A life cycle assessment was also conducted to improve the environmental performance of the steel industry. Results of these assessments revealed that gray water footprint, which is mainly derived from aquatic eutrophication, carcinogens, and non-carcinogens, is higher than blue water footprint. Optimizing indirect processes, including iron ore mining, magnesium oxide production, transportation, and electricity generation, played dominant roles in the reduction of gray water footprint. Furthermore, COD, Cr (VI), phosphate, BOD5, Hg, As, nitrogen oxides, particulates, and sulfur dioxide were the key substances for environmental improvements. The underestimation of direct water footprint showed the importance and urgency of implementing scientific and adequate monitoring indicators. Meanwhile, the environmental burden can be reduced by adopting a reasonable location of the steel industry on the basis of regional water resources and actual transportation status, improving the efficiency of raw material consumption, and optimizing the power structure.